grr@cbmvax.UUCP (George Robbins) (05/31/89)
In article <SMARTIN.89May29072600@iemsun.dhc> smartin@iemsun.dhc (Stephen Martin) writes: > I would like to see a way to NFS mount or remotely link a specific file > without having to mount a whole directory. Have you tried it? Seems to work fine on DEC's Ultrix implementation of NFS. The "mount point" must be a directory, but it turns into a "file" when a remote file is mounted on it. I haven't the faintest idea whether it is "supposed" to work or not, I was a bit surprised when I discovered this "feature" by accident. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
arosen@hawk.ulowell.edu (MFHorn) (06/01/89)
In article <7018@cbmvax.UUCP> grr@cbmvax.UUCP (George Robbins) writes: >In article <SMARTIN.89May29072600@iemsun.dhc> smartin@iemsun.dhc (Stephen Martin) writes: >> I would like to see a way to NFS mount or remotely link a specific file >> without having to mount a whole directory. > >The "mount point" must be a directory, but it turns into a "file" when a >remote file is mounted on it. > >I haven't the faintest idea whether it is "supposed" to work or not, I was >a bit surprised when I discovered this "feature" by accident. I too was surprised to find it work (SunOS 4.0 mounted a DG/UX 4.02 file). But if you stop and think that all diskless clients 'mount' a swap _file_ from the server, it makes some sense that it should work. -- Andy Rosen | arosen@hawk.ulowell.edu | "I got this guitar and I ULowell, Box #3031 | ulowell!arosen | learned how to make it Lowell, Ma 01854 | | talk" -Thunder Road RD in '88 - The way it should've been
guy@auspex.auspex.com (Guy Harris) (06/02/89)
>I too was surprised to find it work (SunOS 4.0 mounted a DG/UX 4.02 file). >But if you stop and think that all diskless clients 'mount' a swap _file_ >from the server, it makes some sense that it should work. The quotes around "mount" are significant. There's no direct connection between the fact that mounting a file accessed over NFS atop a directory works and that attaching a file accessed over NFS as a swap area works. "mounting" a swap file means "getting a file handle for it and associating it with a "swap area" entry; reads from and writes to that swap area get turned into NFS "read" and "write" calls using that file handle. "mounting" something on top of a directory, if the thing being mounted is being mounted over NFS, means "getting a file handle for that something and flagging that something as being 'mounted on' the directory". There's no reason why it must *ipso facto* be possible to mount a non-directory file atop a directory; the implementation happens to let it work, and this may even be deliberate, but I could imagine an implementation that supported attaching files accessed over NFS as swap areas but that got confused by an attempt to mount a file atop a directory (it might not be a *good* implementation, but then I didn't say it was...).